The Marvin Casemaster makes run-of-the-mill casement windows seem, well, run-of-the-mill. From the warm wood interior throgh the finely detailed exterior, Casemasters are solidly engineered for a lifetime of durable, smooth operation. Casemasters include the best designed hardware available, plus a concealed dual-locking mechanism for an airtight seal plus added security. Dual-arm rotogears and heavy-duty hinge arms offer superior sash control, preventing sagging even on tall, heavy units.